Chapter 19: End Cretaceous Mass Extinction

Question 1

What happened at the end of the Cretaceous period?

Answer 1

65-75% of all species were dead

Question 2

What do gradualists believe about this extinctions?

Answer 2

Extinctions took place over a period as great as 1 million years

Question 3

What was the prominent life forms that went extinct?

Answer 3

Dinos
Huge reptilian swimmers
Small plants

Question 4

What are the 2 big holes in the Alvarez theory?

Answer 4

1. No impact site of sufficient side was known
2. Perfect correlation with an enormous eruption of laval in India which would could have supplied the dust, CO2, SO2 and even Ir

Question 5

What are the 2 layers of the K/T boundary?

Answer 5

1. Fireball layer: Top layer, 3mm carbon rich, no variations in thickness
2. Ejecta layer: Bottom layer, 2 cm but varies

Question 6

How and where was the Chicxulub crater found?

Answer 6

1/2 In the ocean of Mexico and on the land near by

Oil company found it while drilling

Question 7

How is the link between the Chicxulub impact and the extinction?

Answer 7

Though the abundant K/T outcrops with thick tsunami generated sandstone layers mourn the Gulf of mexico
-Tsunami layers in the K/T section from sections far away from the impact site

Question 8

How long did the extinction last fro approx?

Answer 8

Extended for up to 1000 years after impacts and probably due to the raised ocean levels and surface temperatures

Question 9

Sequence of events?

Answer 9

1. asteroid collision
2. punched a hole in the atmsphere
3. Yucastan peninsula of mexico
4. front stopped but back was still moving
5. 145-180 km wide, asteroid vaporized as well as the rock
6. Tons of dust created
7. Fragments dropped to earth and caused fireballs
8. Sulpher aerosoles produced, reflecting enough light to stop photosynthesis fro 6 months
9. Tsunami
10. so much CO2 greenhouse effect should have raised the global temp by 15C+ lasted 100 years

Question 10

Was there any evidence that the dinos were in danger of extinction?

Answer 10

No threat from other creatures
One says there was a gradual decline in dino diversity but the same study looked over by another professional said that there was no statistical evidence

Question 11

What species could survive after the impact?

Answer 11

Those who didn’t depend on plants but could live off nutrients of rotting organic matter

Question 12

What was the source of the Deccan Traps?

Answer 12

A mantle plume over the Indian ocean

Question 13

Was the amount of CO2 released from the traps substantial enough to cause global warming?

Answer 13

It did not result in global warming from that period

Question 14

What are we concluding is the main impact event that caused the catastrophe?

Answer 14

Chicxulub was the major factor in influencing global temp and the major impact event